Contact devices of the kind mentioned above are usually part of current transmission systems for electrically operated machines that are connected to an external power source. In particular, contact devices of the kind mentioned above can be used for current transmission of electrically operated vehicles, i.e., for example, for transmitting current via an overhead wire system to the electric drive of a rail vehicle. Contact devices of the above-mentioned kind are used for temporary power transmission in particular in hybrid drive systems, in which another power source is available besides the electrical current supply.
The temporary contact of the contact device to a current-supplying contact conductor arrangement needed in particular for temporary power transmission usually requires an advancing device that is connected to the contact device and may be realized as a lifting device, for example, so as to make the contact strips of the contact device touch the contact conductor arrangement and to interrupt the contact again, if necessary, by removing the contact strips from the contact conductor arrangement. The advancing motions carried out for this purpose by the contact strips require more or less elaborate advancing devices, depending on the size and on installation conditions of the required contact devices, said advancing devices often vastly exceeding both the constructional effort and the production costs for the actual contact device.